A man in the US state of Wisconsin has told police he kept his mother's corpse in a freezer for more than four years while he collected her pension.

Police found a body in a sitting position encased in ice.

Philip Schuth, 52, told police his elderly mother, Edith, died of natural causes in August 2000, but he didn't tell anyone because he was afraid police would blame him, according to documents filed today in court.

He said his mother was attacked by a cat a few years earlier, and her blood was on the walls of the house they shared. He feared police would think he killed her, according to the documents.

Police discovered a chest freezer in Schuth's basement, and after chipping away at a block of ice they uncovered a human knee.

Sheriff's Capt. Jeff Wolf said a body appeared to be in the block, intact in a sitting position. The body has not been identified. An autopsy is planned this week.

Investigators found the freezer at the end of an all-night stand-off at Schuth's home in Campbell, on French Island in the Mississippi River about 177km north-west of Madison.

The stand-off began on Friday when a 10-year-old boy told his father that Schuth had hit him.

The boy's father, mother and the child confronted Schuth at his home. After admitting he hit the boy, Schuth allegedly pulled out a handgun and opened fire.

The father was hit three times, and the family fled and called police. The father was treated and released for his wounds.

Schuth retreated into his house. When SWAT teams arrived, Schuth told negotiators he had "more than 10 but less than 100" bombs and 16 firearms, and it would be "high noon" when he surrendered, according to court documents.

He surrendered early on Saturday without incident. Investigators allegedly found 15 to 20 homemade explosive devices packed with nails, heavy staples and other metal items, a sawn-off shotgun and 15 other firearms.

District Attorney Scott Horne said he planned to charge Schuth next week with attempted homicide and reckless endangerment for allegedly shooting at the family, as well as having improvised explosives and concealing a corpse.

La CROSSE, Wis. (AP) - An elderly woman whose body was kept in the freezer for four years while her son continued to collect her Social Security checks appeared to have died of natural causes, according to autopsy results released Wednesday.

Sheriff Mike Weissenberger said it appeared that the woman died of kidney and heart failure, but pathologists were still awaiting toxicology tests.

The body was found packed in 200 to 300 pounds of ice inside a chest-style freezer in the woman's basement Sunday after a 15-hour police standoff with her 52-year-old son, Philip Schuth, who was arrested on charges of shooting a neighbor.

Schuth told authorities that his mother died naturally in 2000 but that he was afraid he would be blamed